The development, evolution and function of the Bullseye petal pattern in the Hibiscus trionum complex

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Theme: Agriculture and Food SecurityThe development, evolution and function of the "Bullseye" petal pattern in the Hibiscus trionum complex: Identifying the regulatory mechanisms leading to diverse flower patterns Overall aim: Understand the processes accounting for localised accumulation of pigments in proximal and distal petal regions of H.trionum and its close relatives which create their distinctive bullseye pattern. Understanding the role of different bullseye geometries in mediating plant-pollinator interactions. The project is further split into three aims. Aim 1: Identify the regulatory and signalling mechanisms regulating local pigment production in developing petals to generate a bullseye pattern.Computational and Molecular techniques are used to investigate MYB and bHLH candidate genes. Phylogenies; cloning; qPCR for expression; transgenic over-expressor and knock-out lines; Yeast Hybrids. Aim 2: Characterise and compare varieties that differ in their bullseye patterns to understand the developmental and molecular changes accounting for bullseye evolution.Morphological characterisation of pattern variants: pigment extractions; image analysis of petal patterns and features; UV measurements; Molecular changes underlying pattern evolution: H.t.richardsonii transcriptome; qPCR in H.t.commercial and H.t.richardsonii varieties; gene isolation and transgenics in these lines. Aim 3: Explore the role of bullseye pattern in mediating flower-pollinator interaction. Specifically testing the impact of bullseye size variation on pollinator behaviour and assess the relative contribution of each of the three pattern elements (pigmentation, cell shape and cuticular ornamentation) to bullseye function.Question1: Test if variation in bullseye pattern size influences bumblebee (Bombus terrestris) interactions Determine with differential conditioning experiments whether bumblebees can distinguish bullseye patterns exhibiting pigmented regions of different sizes and determine the smallest bullseye size difference bumblebees can perceive.Determine with preference tests if bumblebees favour flowers with a bullseye patterns from a given size range.Question 2: Test the contribution of pigmentation and structural elements to bullseye functionDetermine with preference tests whether pollinators favour patterns composed of structural or pigmentation pattern elements alone, or elements in combination, and therefore whether they use structural or pigmentation, or a combination of both feature types, as cues during an interaction with a flower.